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[v2,0/7] qcom-cpufreq-hw: Add CPU clock provider support

Message ID 20221025073254.1564622-1-manivannan.sadhasivam@linaro.org
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Series qcom-cpufreq-hw: Add CPU clock provider support | expand

Message

Manivannan Sadhasivam Oct. 25, 2022, 7:32 a.m. UTC 
Hello,

This series adds clock provider support to the Qcom CPUFreq driver for
supplying the clocks to the CPU cores in Qcom SoCs.

The Qualcomm platforms making use of CPUFreq HW Engine (EPSS/OSM) supply
clocks to the CPU cores. But this is not represented clearly in devicetree.
There is no clock coming out of the CPUFreq HW node to the CPU. This created
an issue [1] with the OPP core when a recent enhancement series was submitted.
Eventhough the issue got fixed in the OPP framework in the meantime, that's
not a proper solution and this series aims to fix it properly.

There was also an attempt made by Viresh [2] to fix the issue by moving the
clocks supplied to the CPUFreq HW node to the CPU. But that was not accepted
since those clocks belong to the CPUFreq HW node only.

The proposal here is to add clock provider support to the Qcom CPUFreq HW
driver to supply clocks to the CPUs that comes out of the EPSS/OSM block.
This correctly reflects the hardware implementation.

The clock provider is a simple one that just provides the frequency of the
clocks supplied to each frequency domain in the SoC using .recalc_rate()
callback. The frequency supplied by the driver will be the actual frequency
that comes out of the EPSS/OSM block after the DCVS operation. This frequency
is not same as what the CPUFreq framework has set but it is the one that gets
supplied to the CPUs after throttling by LMh.

This series has been tested on SM8450 based dev board with the OPP hack removed
and hence there is a DTS change only for that platform. Once this series gets
accepted, rest of the platform DTS can also be modified and finally the hack on
the OPP core can be dropped.

Thanks,
Mani

[1] https://lore.kernel.org/lkml/YsxSkswzsqgMOc0l@hovoldconsulting.com/
[2] https://lore.kernel.org/lkml/20220801054255.GA12039@thinkpad/t/

Changes in v2:

* Moved the qcom_cpufreq_data allocation to probe
* Added single clock provider with multiple clks for each freq domain
* Moved soc_data to qcom_cpufreq struct
* Added Rob's review for binding

Manivannan Sadhasivam (7):
  dt-bindings: cpufreq: cpufreq-qcom-hw: Add cpufreq clock provider
  arm64: dts: qcom: sm8450: Supply clock from cpufreq node to CPUs
  cpufreq: qcom-hw: Remove un-necessary cpumask_empty() check
  cpufreq: qcom-hw: Allocate qcom_cpufreq_data during probe
  cpufreq: qcom-hw: Use cached dev pointer in probe()
  cpufreq: qcom-hw: Move soc_data to struct qcom_cpufreq
  cpufreq: qcom-hw: Add CPU clock provider support

 .../bindings/cpufreq/cpufreq-qcom-hw.yaml     |  12 ++
 arch/arm64/boot/dts/qcom/sm8450.dtsi          |   9 +
 drivers/cpufreq/qcom-cpufreq-hw.c             | 166 ++++++++++--------
 3 files changed, 118 insertions(+), 69 deletions(-)